One type of display panel which is available commercially at the present time is known as a SELF-SCAN panel. The panel comprises a dot matrix which can be operated to provide a display of alphanumeric characters. Initially, these devices were provided in a size for displaying up to about 30 to 40 characters. However, there is a need for devices which can display a larger number of characters, for example, about 80 or more. Panels of this size cannot be made merely by lengthening all of the parts of smaller panels, and, in addition, in operation, optimum brightness cannot be achieved by operating such panels in known fashion.